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Patented May 8, 1925.

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FRITZ STRAUIB, 0F BASED, AND HEBMANN SCHNEIDER, OF RIEHEN, NEAR BASED,SWITZERLAND, ASSIGNOES TO THE FIRM SOCIETY OF CHEMICAL INDUSTRY INBASLE, or BASEL, SWITZERLAND.

PRODUCTION OF AZO-DYESTUFFS CONTAINING TWO HYDROXYNAPI-ITHALENE NUCLEI.

No Drawing. Application filed April 7, 1926, Serial No. 100,440, and inSwitzerland April 25, 1925.

The present invention deals with an improvement 1n the production of thedyestuffs disclosed in the United States Patent No. 1521.206 which havepresumably the en a i c 2: eral formula:

presence of a water-soluble organic com pound having hydroXyl-groups,for example a carbohydrate, such as glucose or cane sugar, an alcohol,such as glycerine or glycol, or a more complex compound, such as tannin,gallic acid or sulfite cellulose waste liquor. As reducing agentsthemselves there are particularly suitable alkali sulfides, such assodium sulfide, sodium sulfhydrate or sodium polysulfide, as has alreadybeen disclosed in U. S. patent specification 1,521.206.

Example 1.

A suspension, as concentrated as possible, of the dyestulf made bycoupling 150 parts of a-naphthol with 295 parts of nitrated diazotized1-amino-2-hydroxynaphthalenelsulfonic acid is mixed, while stirring,with 25 parts of glycerine or glucose, 14;) parts of caustic sodasolution of per cent strength and 360 parts of crystallized so diumsulfide, all added in succession, and the mixture is further stirred atthe ordinary temperature until the sodium sulfide has disappeared. Thewhole is now diluted with water, common salt added and the dyestufiseparated by addition of acid until the alkaline reaction can no longerbe detected. The dyestuff obtained shows the properties of that obtainedin accordance with the United States Patent No. 1,521,206 but its yieldis considerably better than when it is made by the procedure describedin that patent. 1

Similar result-s are obtained when other additions containinghydroXyl-groups, such as are hereinbefore referred to, are used.

Example 2.

To a concentrated suspension of the dyestuft made by coupling 160 partsof B-naphthol with 295 parts of the nitrated diazo compound of1-amino-2-hydroxynaphthalene-Q-sulphonic acid-are successively addedwhile stirring, 25 parts of glycol or 25 parts of cane sugar, 145 partsof caustic soda solution of 30 per cent strength and 360 parts ofcrystallized sodium sulfide, and the whole is warmed at 8090 C. untilthe sodium sulfide has disappeared. The dyestuff is then worked up asdescribed in the preceding example. It is identical with thecorresponding dyestufi made in accordance with the United States PatentNo. 1,521,206 but is obtained in considerably better yield.

Another hydroXyl-compound can be used instead of glycol or cane sugar.

What we claim is:

1. In the manufacture of dyestuffs capable of being chromed by treatingwith a reducing agent an azo-dyestulf derived from nitrated diazotizedl-amino-2-hydroxynaphthalene--sulfonic acid and a naphthol. theimprovement which consists in conducting the reduction in presence of awater-soluble organic compound containing hydroxylgroups.

2. In the manufacture of dye-stuffs capable of being chromed by treatingwith a reducing agent an azo-dyestuit derived from nitrated diazotized1amino-2-hydroxynaphthalene-d-sulfonic acid and a naphthol, theimprovement which consists in conducting the reduction with an alkalisulfide in presence of a water-soluble organic compound containinghydroXyl-groups.

3. In the manufacture of dyestuifs capable of being chromed by treatingwith a reducing agent an azo-dyestufl derived from nitrated diazotized1-amino-2-hydroxynaphthalenel-sulfonic acid and a naphthol, theimprovement which consists in conducting the reduction in presence ofpolyhydroxy alcohols.

4. In the manufacture of dyestuffs capable of being chromed by treatingwith a reducing agent an azo-dyestufi' derived from 'nitrated diazotized1amino-2hydroxynaphthalene-t-sulfonic acidand .a naphthol, theimprovement which consists in conducting the reduction with an alkalisulfide in presence of polyhydroxy alcohols.

5, In the manufacture of dyestuffs capable of being chromed by treatingwith a reducing agent an azo-dyestufl' derived from nitrated diazotizedl-amino-Q-hydroxynaphth.alene4-sulfonic acid and a naphthol, the

improvement which consists in conducting the reduction in presence ofpolyhydroxy alcohols containing at most 3 carbon atoms.

In the manufacture of dyestuffs capable of being chromed by treatingwith a reducing agent an azo-dyestuff derived from nitrated diazotized lamino-fz-hydroxynaphthalene-t-sul fonic acid and a naphthol, theimprovement which consists in conducting the: reduction with an alkalisulfide in presence of polyhydroxy alcohols containing at most 3 carbonatoms.

7. In the manufacture of dyestufl's capable of vbeing chromed bytreating with a reducing agent an azo-dye stufi' derived from nitrateddiaiotiz'ed l amino 2 hydiioxynaphthalenei-sulfonic acid 'naphthol', theimprovement which consists in conducting the reduction in presence ofglycerine.

8. In the manufacture of dyestuifs capable of being chromedby treatingwith a ,reducing agent an azo-dyestuff derived from nitrated diazotizedl-amino-2-hydroxynaphthalene--sulfonic acid and a naphthol, theimprovement which consists in conducting the reduction with'an alkalisulfide in presence of glycerine.

In witness whereof we have hereunto signied our names this 27th day ofMarch, 192

FRITZ STRAUB. HERMANN SCHNEIDER.

